This invention relates to a method and apparatus for winding and inserting coils into a dynamoelectric machine stator core. More particularly, the invention relates to wave winding coils and inserting the coils into the slots of a dynamoelectric machine stator core.
There has been an increased need for very small, multiphase electric motors for use in automobiles and the like to perform various functions.
However, prior art motor coil winding and insertion methods have not been adapted to small motors. One prior art method for manufacturing the stators for multiphase alternating current dynamoelectric machines has been to wind a coil for each phase and each pole and to insert the coils into the slots of the core of a dynamoelectric machine, more commonly called a stator core. Since each of the coils has two leads, one problem with this method is the difficulty of handling and connecting the many leads. Thus for a three phase, four pole motor, twenty-four leads would have to be handled and connected with this prior art method.
An improvement upon this prior art winding and inserting method is to provide consequent windings for the stator which would result in a total of six coils for a three phase, four pole motor. This method thus results in a total of twelve leads to be handled and connected.
A further improvement is to use the wave winding method for manufacturing the coils since this method results in three coils and a total of six leads. While the wave winding method has advantages, one of the problems with this method is that the prior art equipment for winding, forming and inserting such coils is relatively bulky and because of space requirements, needs to be located outside the insertion tooling blade array. When a winding has been wound on a coil form and then formed or shaped, the winding must be stripped from the coil form onto the insertion tooling. Prior art wave winding equipment and methods have been limited to manufacturing relatively large motors. This prior art equipment has not been successful in manufacturing small motors since the wave winding forming elements could not be moved inside the circular array of blades of the inserting tooling.
In one prior art wave winding and inserting machine a circular coil is first wound and a set of pulling members restrains portions of the coil from radial inward movement while a set of pushing members pushes alternating sections of the coil radially inwardly, thus forming a star shaped winding. The winding is then stripped from the winding and former tooling and placed on the insertion tooling. By necessity, due to the size of the pushing and pulling elements, these members are located outside the insertion tooling blade array. Due to the inherent resilience or springiness of the coil wire, it is difficult to reliably transfer coils so formed to the insertion tooling.
In another prior art machine, a curved set of forming members is located above the insertion tooling blade array and the forming elements have slots cut in their bottom surfaces so that the top edges of the insertion blades can be located therein during the transfer of the coils into the inserting tooling. Thus, the front surfaces of the forming member are disposed within an extension of the interior of the circular array of blades. This method only partially solves the transfer problem since the forming members are not located inside the blade array. Furthermore, since the forming members are still relatively bulky they cannot be made small enough to transfer the windings for very small motors such as, for instance, motors having a stator core bore of one inch or less.
One prior art method for manufacturing these motors has been to increase the size of the bore of the stator core and the stator core slots, thus resulting in less stator core material and poor slot fill and less efficient motors.
What is therefore desired is to provide a method and apparatus whereby wave windings may be formed and inserted in very small stator cores and wherein the forming members extend into the interior of the insertion blade array for positive transfer of the windings into the insertion tooling.